The present invention relates to a bottom bracket and more particularly, to a bottom bracket for a bicycle, which provides an excellent positioning feature for an axle thereof.
A conventional bottom bracket of a bicycle is shown in FIG. 1, which includes a housing 70, a tube 80, an axle 90, a first bearing 902 and a second bearings 903, the housing 70 having a first open end which has an inner threaded periphery defined therein and a second open end which has another inner threaded periphery defined therein, the tube 80 received in the housing 70 and having a first end with an outer threaded periphery defined therein for engagement with the inner threaded periphery of the first end of the housing 70 and a second end. A first recess 801 and a second recess 802 are respectively defined in each inner periphery of the first end and the second end of the tube 80, the axle 90 extending through the tube 80 and having a groove 91 defined in an outer periphery thereof near the second of the tube 80 for receiving the second bearing 903 between the second recess 802 of the tube 80 and the groove 91. A first cap 71 and a second cap 7 each having a central hole defined therein for the axle 90 extending therethrough are respectively engaged to the first end and the second end of the housing 70 for preventing dust from entering therein, the second cap 72 has a tubular portion 720 extending from a side thereof toward the first end of the housing 70 and disposed between the second end of the tube 80 and the second end of the housing 70, the tubular portion 720 has an outer threaded periphery 711 for engagement with the inner threaded periphery of the second end of the housing 70. The first bearing 902 is rotatably received between the first recess 801 of the tube 80 and a race 92 which is force-fitted around the axle 90. A first seal 93 and a second seal 94 are respectively engaged between the axle 90 and the tube 80 for protecting the first and the second bearings 90, 903 from dust entering therein.
However, there are only the race 92, the first and the second seals 93, 94 disposed between the axle 90 and the tube 80 such that the axle 90 tends to be loosened when the bicycle ridden over a rugged road.
The present invention provides a bottom bracket which has a tube having a first end with a hole defined therein which has an inner tapered periphery for engagement with a tapered flange extending from the axle and a second end with a plurality of hook elements for engagement with a cap so as to mitigate and/or obviate the above-mentioned problem.